1. Field of the Invention
The present invention relates to an image processing apparatus for generating a three-dimensional shape image from a plurality of two-dimensional subject images, an image processing system and an image processing apparatus operation method.
2. Description of the Related Art
Conventionally, a technique of constructing a three-dimensional shape from two-dimensional images has been proposed. Only a partial three-dimensional shape corresponding to the two-dimensional image corresponding to the one frame can be constructed as a three-dimensional shape that can be constructed from a two-dimensional image corresponding to one frame. Therefore, a technique of constructing a three-dimensional shape of an entire target organ using two-dimensional images corresponding to a plurality of frames obtained by observing the entire organ is also proposed.
For example, Japanese Patent No. 5354494 describes a three-dimensional image generation apparatus generating a three-dimensional image (for example, a virtual endoscopic image) having a high resolution and is provided with color information. More specifically, in the technique described in the above official gazette, only pixels, for example, on a circular test line are extracted and one-dimensionally developed, for each of a plurality of frame images. Furthermore, by combining a plurality of one-dimensionally developed pixel strings, a two-dimensional image of an inner wall of a tubular structure being planarly developed is generated. The generated two-dimensional image is divided in a grid shape. Three-dimensional coordinates (x, y, z) (model space coordinates) are calculated based on luminance information on each coordinate on the two-dimensional image to generate a three-dimensional model. Then, by attaching texture of the two-dimensional image to the three-dimensional model based on two-dimensional coordinates and the three-dimensional coordinates, a three-dimensional model is generated.
In order to accurately generate the two-dimensional image of an inner wall of a tubular structure planarly developed in such a technique, it is necessary to grasp a positional relationship among the plurality of one-dimensionally developed pixel strings, and 6-degree-of-freedom information about an endoscope to acquire the frame images, that is, a three-dimensional position (three-dimensional translational-degree-of-freedom information), a rotational degree of freedom around an optical axis of an optical system of the endoscope, and each of pieces of information about rotational degrees of freedom around two axes orthogonal to the optical axis are required.